Table 2 Comprehensive overview of CNN Layers used by the Proposed Hybrid Model.

From: Advanced air quality prediction using multimodal data and dynamic modeling techniques

Layer type

Input dimensions

Output dimensions

Activation

Filters/Units

Kernel size/stride

Purpose

Input Layer

(128 × 128 × 3)

(128 × 128 × 3)

N/A

N/A

N/A

Accept raw satellite imagery data and Sensor Grid Data

Conv2D Layer 1

(128 × 128 × 3)

(128 × 128 × 32)

ReLU

32

(3 × 3/1)

Extract basic spatial features

MaxPooling-2D Layer 1

(128 × 128 × 32)

(64 × 64 × 32)

N/A

N/A

(2 × 2/2)

Downsample feature maps

Conv-2D Layer 2

(64 × 64 × 32)

(64 × 64 × 64)

ReLU

64

(3 × 3/1)

Extract deeper features

MaxPooling-2D Layer 2

(64 × 64 × 64)

(32 × 32 × 64)

N/A

N/A

(2 × 2/2)

Further, it reduces spatial dimensions

Fully Connected 1

(32 × 32 × 64)

512

ReLU

512

N/A

Learn high-level feature representation

Fully Connected 2

512

256

ReLU

256

N/A

Further abstraction for pollutant level

Output Layer

256

1 (or n classes)

Linear/SoftMax

1/n

N/A

Predict AQI or pollutant concentrations